Collapsible  golf bag cart with improved folding mechanism

ABSTRACT

A collapsible golf bag cart with improved folding mechanism ( 10 ) is provided for converting between an expanded mode ( 14 ) for use on a golf course and a compact mode ( 16 ) for storage. A pivot joint subsystem ( 26 ) includes a rotating reciprocal gear assembly ( 120 ). The cart ( 10 ) is characterized by having equal length base struts ( 34 ), torso struts ( 32 ) and leg struts ( 70 ). Handle grips ( 138 ) are mounted on grip pivots ( 140 ) so as to be lockable in multiple vertical orientations for the user to adjust for optimally controlling the cart ( 10 ).

This is a non-provisional application, claiming priority from U.S. provisional applications Nos. 61/608,503 by one of the same inventors, filed 8 Mar. 2012, and 61/692,575 by the same inventors, filed 5 Sep. 2012.

TECHNICAL FIELD

The present invention relates generally to accessories for golfers and particularly to golf bag carts (push carts) and methods for transporting golf bags used by golfers.

BACKGROUND ART

Although the purists in the golf community insist that the only way to properly play golf is to carry the golf bag, either personally or through the use of a caddy, many golfers prefer to use carts to transport the golf bags and associated equipment. While riding carts are required by many courses, a great number of players desire to gain the exercise benefits of walking during the round, without carrying the bag and equipment. For this reason walking carts are popular.

For many years pull carts, usually two-wheeled, were the norm. However, with the introduction in 2000 of the SPEED CART® three-wheeled push cart (U.S. Pat. Nos. 6,698,789 and 7,128,333) from Sun Mountain Sports, Inc. the landscape changed. Push carts, particularly collapsible push carts, have become the most popular versions.

Developments have continued, including the inventor's own Micro-Cart® model, also from Sun Mountain Sports, Inc. which reduced the size and weight of the cart, particularly of the footprint in the compact mode.

Nonetheless, demand continues for more compact, more stable, more convenient and lighter golf bag carts.

DISCLOSURE OF INVENTION

Accordingly, it is an object of the present invention to provide an improved collapsible golf bag cart for transporting a golf bag in a highly stable manner.

Another object of the invention is to provide a bag cart system which transitions by expansion and collapsing between a folded (compact) state and an expanded (operational) state with minimal effort and an elegant mechanism.

A further object of the present invention is to provide a bag cart system with improved geometry for greater stability and strength per weight than prior versions.

Yet another object of the invention is to provide a cart which collapses into a compact mode which has a minimal footprint and a minimal height.

Another object of the invention is to provide a multi-position handle arrangement for the convenience of the golfer, allowing the golfer to propel the bag cart from behind or from the side.

Still another object of the invention is to provide a cart structure where each of the folded components has approximately the same longitudinal extent, for minimal folded size.

Yet another object is to provide a cart structure where the folded components nest effectively with each other for compactness.

Briefly, one preferred embodiment of the present invention is a golf bag push cart having a base frame, a torso frame, and a rear wheel subassembly, all radially extending from a central pivot joint subassembly, with a front wheel subassembly, a handle subassembly pivotally mounted on the distal ends of the frame components. The pivot joint includes a central transverse axle and a reciprocal rotational gear (RRG) assembly which operate together to control the positioning of the rear wheels in accordance with the relative rotational positions of the base frame and torso frame of the bag support system. Rotationally separating the torso frame and the base frame operates the RRG to rotate the rear wheel position rearward and laterally expand the position outward from a compact (folded) mode to an expanded mode for use by a golfer. The front wheel subassembly and the handle subassembly are separately manually expanded. Top and bottom bag cradles are provided on the bag support to receive a golf bag for rolling transport. The handle subassembly includes handle grips which are pivotally mounted to adjust to most efficient vertical position for the user's convenience.

An advantage of the present invention is that it provides great stability: with a substantial rear wheel base in the expanded mode; a central pivot point for the rear wheels; and a centralized balance point (with a center of gravity relatively low to the ground).

Another advantage of the invention is that it has a wheelbase which is greatly expanded on two axes when expanded, thus providing excellent stability when loaded with a golf bag.

Yet another advantage of the present invention is that the tapered shapes of each extension from the central pivot point and the cast or extruded construction of structural components provide optimal strength while the lightweight materials result in a lightweight cart which is easily lifted and handled by most golfers.

Still another advantage of the present invention is that the compound actions provided by the unique RRG pivot joint structure for the wheels and the frame members results in greater height and width in the use mode, without sacrificing stability.

A still further advantage of the present collapsible golf bag cart invention is that the dual front wheel yoke facilitates folding until the common axle hits the base frame, with the front wheels passing under and past the base frame, nesting inside the rear wheels, for minimal height in compact mode.

Yet another advantage of the present invention is that the lateral spacing of the components allows each to nest effectively with the others, minimizing the width and height of the compact mode.

Another advantage of the present invention is that the base struts, torso strut and leg struts are shorter in length than in prior folding carts, as facilitated by the central pivot axle, which provides greater overall strength with lighter materials.

These and other objects and advantages of the present invention will become clear to those skilled in the art in view of the description of the best presently known mode of carrying out the invention and the industrial applicability of the preferred embodiment as described herein and as illustrated in the several figures of the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The purposes and advantages of the present invention will be apparent from the following detailed description in conjunction with the appended drawings in which:

FIG. 1 is a perspective view of the expanded mode of the present invention;

FIG. 2 is a front view of the invention in the expanded mode of the invention;

FIG. 3 is a rear plan of the expanded mode of the invention;

FIG. 4 Is a perspective view of the compact mode of the present invention;

FIG. 5 is a top plan view of the golf bag cart of the present invention, shown in the folded mode;

FIG. 6 is a side elevational view of the preferred embodiment in the compact mode;

FIG. 7 is a detail front right perspective view of the pivot joint subassembly;

FIGS. 8 a and 8 b are opposing perspective detail views of the interior components of the pivot joint subassembly, without the frame and leg members attached; and

FIGS. 9 a, 9 b, and 9 c are partially cut away side detail views of the pivot joint subassembly, shown respectively in the expanded, transitional, and compact mode positions.

BEST MODE FOR CARRYING OUT THE INVENTION

The present invention is collapsible golf bag cart with improved folding mechanism used to transport golf bags loaded with golf clubs and accessories. The collapsible cart is referred to by the general reference character 10 in the drawings and description. The collapsible cart 10 may be used with various golf bags and may exist in multiple embodiments.

In one preferred embodiment of the invention illustrated in FIG. 1, the collapsible cart 10 is shown in a perspective view as appropriate for transporting a typical golf bag 12 (not shown). The cart 10 is illustrated in FIGS. 1-3 in an expanded mode 14, also known as the “use” mode, where it is capable of carrying and transporting the golf bag 12. The invention is illustrated in FIGS. 4-6 in a compact mode 16 or “folded” mode where it is collapsed into a minimal volume configuration for storage in an auto trunk compartment or garage, for example.

The preferred embodiments 10 are generally laterally symmetrical about a vertical plane 18 (see, especially, FIGS. 2, 3 and 5) with corresponding left and right components (or components which are bisected by the plane 18). The cart 10 may be thought of as having various principal assembles or subsystems which operate together in order to function as a compact, lightweight and extremely easy to use method of transporting a golf bag on the rolling surfaces of a golf course and in other locations such as parking lots and storage facilities. The primary subassemblies include a bag support frame 20, a front wheel subassembly 22, a rear wheel subassembly 24, a pivot joint subassembly 26, and a handle subassembly 28. It is understood that some components of the invention interface with others and may be considered to be a part of more than one of the subassemblies. The pivot joint subassembly 26 is the fulcrum and central component of the overall cart 10 so terms such as proximal and distal refer back to that component.

The bag support subassembly includes a base frame 30 on one side of the pivot joint subassembly 26 and a torso frame 32 on the other. The preferred base frame 30 includes a pair of symmetrical base struts 34, each pivoting at the proximal end on the pivot joint 26 and being spanned by a cross pin 36 at the distal end, with an intermediate gap 38 therebetween. As shown particularly in FIG. 1, each base strut 34 is tapered so as to have a greater vertical height at the proximal end and a lesser height at the distal end. The base frame 30 and the torso frame 32 have approximately the same longitudinal length.

A bottom bag cradle 40 is mounted on the cross pin 36 so as to pivot over a limited arc from a support position (FIGS. 1-3) to a storage position (FIGS. 4-6).

The torso frame 32 has only a single torso strut 42 in the preferred embodiment. The torso strut 42, like the base struts 34 is tapered from its proximal end at the pivot joint 26 to its distal end. The proximal end of the torso strut 42 interfaces with the pivot joint 26 intermediate the two base struts 34 and is adapted to nest into the intermediate gap 38 in the compact mode 16 (FIGS. 4 and 5). The distal end of the torso strut 42 includes a dogleg 44 which terminates at a toothed handle attachment pivot 46 while a top bag cradle 48 is attached at a top cradle mount 50 situated at or near the dogleg 44. The top bag cradle 48 is adapted to elastically and mechanically adjust to receive and support the upper portion of the golf bag 12 to keep it in position during use.

The front wheel subassembly 22 includes a yoke 52 pivotally mounted on the cross pin 36. The yoke 52 includes a pair of yoke arms 54 spaced apart just wider that the width of the base frame 30 such that in the compact mode 16, the yoke arms 54 may nest about the base struts 34 (see FIG. 5). Each yoke arm supports an exterior axle 56 upon which a corresponding front wheel 58 is mounted. In this manner the front wheels 58 do not block the space between the yoke arms 54 and inhibit minimal space nesting. A yoke lock lever 60 is provided at one end of the cross pin 36 to manually lock the yoke 52 in the expanded mode 14 of FIGS. 1-3 or the compact mode 16.

The rear wheel subassembly 24 also pivots and expands laterally and rearward from the pivot joint 26. The entire rear wheel subassembly 24 has approximately the same longitudinal length as do the base struts 34 and torso strut 42. As with the other main components, the the rear wheel subassembly 24 is symmetrical about the bisecting plane 18 and includes a pair of symmetrical suspension subsystems 62, spaced to each side of the bisecting plane 18 (see FIGS. 2, 3 and 5, particularly). In each suspension subsystem 62, a central axle 64 extends into the pivot joint subassembly 26 (see further discussion with respect to FIGS. 7, 8 and 9) and attaches to a spacer bracket 66 upon which a mounting plate 68 is secured. In at least the preferred embodiment, the spacer bracket 64 is integrally formed with the mounting plate 68 to form a single unitary piece.

The suspension subsystems 62 are a variation on the inventor's parallelogram suspension systems found on prior golf bag carts of Sun Mountain Sports, Inc. (see, e.g. U.S. Pat. Nos. 6,698,789 and 7,128,333). In the present case, a broad tapered structural leg strut 70 is pivotally mounted on the mounting plate 68 at its proximal end and to an axle pivot bracket 72 at its distal end. In parallel array to the leg strut 70, a parallel link 74 member is also pivotally connected to the mounting plate 68 and the axle pivot bracket 72. On at least one side of the cart, a manually activated pin and gap brake 75 is placed intermediate the axle pivot bracket 72 and a rear wheel 76. The rear wheels 76 are then rotationally supported on rear axles 78 associated with the axle pivot brackets 72. As described in the inventor's prior patents, this parallelogram suspension method maintains extremely stable and secure positioning and support of the rear wheels 76 in the expansion mode 14, the compact mode 16 and during the transitions between these modes.

The structures associated with and/or parts of the spacer bracket 66/mounting plate 68 are best illustrated in FIGS. 7, 8 a, and 8 b. A strut bracket 80 is centered on the origin of the circular mounting plate 68 for mounting the associated rear leg strut 70 thereon, utilizing a strut pin 82 which extends though the leg strut 70 on each side of the strut bracket 80, through the portions of the strut bracket 80 on each side of the central axle 64 and also through the central axle 64 itself. The leg strut 70 pivots about the strut pin 82 and includes an extension portion 84 which extends beyond the fulcrum provided by the strut pin 82.

Similarly, a link bracket 86 is provided parallel to and separated from the strut bracket 80 to pivotally mount the proximal end of the parallel link 74. A link pin 88 (see FIG. 2) pivotally supports the parallel link 84.

An expansion slide aperture 90 for slidably receiving an expansion slide post 92 extends axially though the mounting plate 68 and the associated spacer bracket 66 at a position radially offset from the central axle 64 opposite the side of the link bracket 86. Similarly, a retraction slide aperture 94 receives a retraction slide post 96 at a position radially offset toward the link bracket 86.

It may also be seen in the illustration of FIG. 7 that the interior facing surfaces of the proximal ends of the base struts 70 are provided with a leg deployment ramp 98 which interacts with the expansion slide post 92 and the retraction slide post 96 as hereinafter described.

The pivot joint subassembly 26, and particularly the transverse central axle 64 which extends therethrough, constitute the core fulcrum component of the present invention 10 in that the positioning and alignment of all of the other subassemblies are primarily controlled by this structure. The pivot joint subassembly 26 is best understood in connection with FIGS. 7, 8 (8 a and 8 b) and 9 (9 a, 9 b and 9 c). In FIG. 7 a, a detail right front perspective view of the fully assembled joint structure 26 is shown in the expanded mode 14, while in FIGS. 8 a and 8 b the interior components of the joint are shown in different perspectives. FIGS. 9 a, 9 b and 9 c illustrate a cut-away side view of the joint 26, with FIG. 9 a illustrating the situation in the expanded mode 14, FIG. 9 c showing the compact mode 16, and FIG. 9 b illustrating an intermediate position during transition. It is noted that the opposite side base strut 34 is shown, with the near side base strut being cut away, so the internal elements shown are not the ones associated with the base strut illustrated.

In FIGS. 7 it may be seen that the central axle 64 (which extends completely through the pivot joint subsystem 26) and the spacer brackets 66/mounting plates 68 all laterally extend beyond the base struts 34. The torso frame 32 is fixedly attached to joint subassembly 26 on the bisecting plane 18, such that moving the torso strut 42 acts to rotate the central axle 64 (as discussed below with respect to FIG. 9). A protective sheath 100 minimizes the amount of dirt, dust and other foreign matter into the interior of the joint 26. Side sheaths 102, not shown in FIG. 7, but see especially FIGS. 2, 4 and 5, extend over the spacer brackets 66 and the central axle 64 between the base struts 34 and the mounting plates 68 to prevent influx of fouling agents from those directions.

The inner workings of the pivot joint subassembly 26 are shown particularly in FIGS. 8 and 9 and the following discussion deals with both illustrations, with some elements being more prominent in one figure or another.

As shown in FIGS. 8 and 9, a pair of partially internally toothed ring gears 104 are provided about, but not directly connected to, the central axle 64. Each ring gear 104 is fixedly connected to a corresponding base strut 34 by connecting bolts 106. The base frame 30 and the ring gears 104 provide the “rotationally stationary” components of the cart 10, with everything else being supported thereby.

Radially within each ring gear 104, surrounding and affixed to the central axle 64, is a central gear 108. Mounted intermediate the central gear 108 and the ring gear 104 are a ratio gear 110, an interior reversing gear 112 and an exterior reversing gear 114. The ratio gear 110 and the interior reversing gear 112 are axially offset and (in the preferred embodiment) affixed to each other to be commonly carried on an interior shaft 116 with the ratio gear 110 mating with the central gear 108. Similarly, the exterior reversing gear 114 is carried on an exterior shaft 118 and mates with both the interior reversing gear 112 and the corresponding ring gear 104. The interior shaft 116 and exterior shaft 118 each pass through (with at least the interior shaft 116 being rotationally free on bearings in the preferred embodiment) the torso strut 42, so as move therewith (see FIG. 9). Each set of gears is duplicated on each side of the bisecting plane 18 to provide stability and balance, with each ring gear 104 being associated with one of the base struts 34. Together, the various gears components form a reciprocal rotational gear (“RRG”) assembly 120. The RRG assembly 120 facilitates the conversions between the expanded mode 14 and the compact mode 16, as shown in FIGS. 9 a, 9 b, and 9 c.

A stop wedge 122 is provided on each central gear 108 to, at the extremes of rotation of the central axle 64, abut against a fixed expansion limiter 124 and compact limiter 126. The limiters 124 and 126 are mounted on the torso strut 42.

A spring loaded pivot lock lever 128 is pivotally affixed to, extends about and brackets the torso frame 32. The pivot lock lever 128 is used to lock the rotational position of the torso strut 42 in place in the expanded mode 14 or is pressed to release the torso strut 42 to rotate the central axle 64 with respect to the base frame 30 in order collapse the cart 10 into the compact mode 16. The spring mounted pivot lock lever 128 (see FIGS. 8 a and 8 b) raises or lowers a catch pin 130 which will engage an expanded slot 132 on the ring gear 104 in the expanded mode 14 (FIG. 9 a), ride on the exterior surface of the ring gear 104 in transition (FIG. 9 b) and engage a compact slot 134 in the compact mode 16 (FIG. 9 c). This facilitates locking the cart 10 into either the expanded mode 14 for use on the course or the compact mode 16 for storage, with an easy transition therebetween.

The operation of the pivot joint assembly 26 is primarily illustrated in FIGS. 9 a-9 c. In the view of FIG. 9 a, the cart 10 is shown in the expanded mode 14, with the torso frame 32 being at about a 130° angle to the base frame 30 and the leg strut 70 extending rearward from the pivot joint 26 and outward from the center plane 18. This is the same condition illustrated in FIGS. 1 and 7, with the rear wheel assemblies supporting the pivot joint 26 substantially above the ground surface. The pivot lock lever 128 is engaged; with the catch pin 130 engaged with the expanded slot 132. The central gear is positioned such that the stop wedge 122 is abutting against the expansion limiter 124.

Conditions exterior to the cutaway of FIG. 9 a are shown in FIG. 7. When the central axle 64 is rotated to this extent, the mounting plate 68 is rotated such that the leg deployment ramp 98 engages the retraction slide post 96 to a minimal degree and the expansion slide post 92 to the maximal degree. This causes the expansion slide post 92 to protrude through the mounting plate 68 and force the leg strut 70 outward (the rotation of the central axle 64 forces the leg strut 70 backward). It is noted that when the rotation to the compact mode 16 occurs, the opposite condition obtains and the retraction slide post 96 is forced outward against the extension portion 84 such that the leg strut 70 is urged inward toward the frame.

When it is desired to fold the cart 10 into the compact mode 16, the pivot lock lever 128 is disengaged and the catch pin 130 is released from the expanded slot 132 and rides along the outside of the ring gear 104. In the transitional mode illustrated in FIG. 9 b, the torso frame 32 has been rotated to an angle of about 60° to the base frame 30. The rotation of the torso strut 42 causes the interior shaft 116, the exterior shaft 118, and their associated gear components in the RRG assembly 120 (ratio gear 110, interior reversing gear 112 and exterior reversing gear 114) to move accordingly with respect to the central gear 108. In this manner the interaction between the ring gear 104 and the exterior reversing gear 114 rotates the interior reversing gear 112 to drive the interior shaft 116 such that the ratio gear 110 engages the central gear 108 and drives it in the opposite direction to the rotation of the torso frame 32. This rotates the central axle 64 to drive the rear wheel suspension systems 62 forward as the retraction slide post 96 forces the rear wheels 76 inward. During this transition the pivot joint 26 will begin to descend toward the ground surface, once the leg suspensions 66 begin to approach parallel with the base frame 30.

When the rotational limit is reached, as shown in FIG. 9 c, the central gear 108 will have been driven such that the stop wedge 122 abuts against the compact limiter 126 and the catch pin 130 snaps into the compact slot 134. In this position, the base frame 30, the torso frame 32 and the leg struts 70 are all generally co-aligned, as shown in FIG. 6, and the cart 10 is ready for storage.

Turning now to the handle subassembly 28 as shown in FIGS. 1-3, an open-Y-shaped handle frame 136 is pivotally attached in a lockable ratchet manner to the handle pivot 46 at the upper end of the torso frame 32 such that the angle of the handle subassembly 28 with respect to the torso frame 32 may be adjusted for the user's comfort. In addition to the handle frame 136, the handle subassembly 28 includes a pair handle grips 138 at the upper lateral extents.

In the preferred embodiment, each handle grip 138 is individually pivotally attached to the handle frame at a grip pivot 140 so that it may rotate to different vertical orientations for the convenience of the user. This allows the handle grips 138 to be position to extend generally outward (FIGS. 1-3), fold down to a compact position, (FIGS. 4-6) or rotate upward for easy gripping from the side of the cart 10, when the user wishes to guide the cart from the side. The grip pivot 140 is preferably a ratchet structure mating with the grip handle 138 and being lockable by the user in any position within the range of rotation. This facilitates the user maneuvering the cart 10 while being positioned behind behind it or walking along side of it so as to control the cart 10 with one hand.

The handle subassembly 28 of the preferred embodiment 10 also may include a variety of convenience features for the use of a golfer during a round of golf. As these are not critical to the present invention they are not specifically shown or enumerated in the drawing, but are described in the inventor's prior patents applications. One feature which is shown is a storage console 142 with a lid 144 hingedly attached thereto. The storage console 140 provides a compartment where the golfer can place yardage books, golf balls, notes, a slim wallet or other items to which occasional access may be desired during the round. Other features such as tee apertures and pencil apertures may be formed in the extended frame of the console 142 to receive and store frequently accessed golf tees and pencils during the round. Additionally and optionally, the cart 10 may include a drink holder.

A further innovation inherent in the preferred deluxe embodiment of the invention is a score card plate 146. The score card plate 146 may either be fixed in a 90° angle to the handle frame 134 (See FIGS. 4 and 6) or may be rotatably mounted to adjust to a comfortable angle for use by the golfer. Various mechanisms (clamps, magnetic retainers or the like, may be utilized to affix a score card to the score card holder 146.

In order to minimize wobble or similar problems which may be caused by imperfect manufacturing tolerances, it is desirable to provide mechanisms for adjusting the spacing of some of the elements in the vicinity of the pivot joint subassembly 26. To maintain axial pressure between the spacer brackets 66/mounting plates 68 and the central gears 108 a pair of threaded adjustment sockets 148 are provided in each mounting plate 68 (See FIG. 8 b) to receive a first adjustment screw 150 and a second adjustment screw 152. The preferably Allen-headed adjustment screws 148 and 150 extend through to abut against a spacer plate 154 (See FIGS. 7, 8 a and 8 b) such that proper axial tension may be maintained.

It is also particularly desirable that a firm pressure be maintained for the expansion slide post 92 against the leg deployment ramp 98 for proper functioning. To this end an expansion adjustment screw 156 extends through each leg strut 70 (see FIGS. 1, 4 and 6) to abut against the distal end of the expansion slide post 92. Tightening the Allen-headed expansion adjustment screw 156 maintains firm contact between the proximal end of the expansion slide post 92 and the leg deployment ramp 98.

It is noted that, while the RRG 120 greatly facilitates folding and unfolding the cart 10, an alternate embodiment is envisioned where the torso frame is completely independent of the central axle 64. In such an embodiment the expansion and retraction of the rear leg assembly 28 may be accomplished manually. Grasping a rear wheel 78 and manually rotating the central axle 64 will cause the interaction of the leg deployment ramp 98 with the slide posts 92 and 96 to force the distal ends of the leg struts 70 inward or outward (depending on the direction of rotation) in conjunction with the rotation. The torso frame would then be independently extended or folded inward, either before or after the legs and wheels.

The preferred embodiment is primarily constructed of cast anodized aluminum for light weight and durability. The wheels 58 and 76 are formed of lightweight structural plastic with cushioned traction surfaces and may either be provided with solid hubs or spoke hubs. In some embodiments rubberlike friction surfaces are also provided.

Many modifications to the above embodiment may be made without altering the nature of the invention. The dimensions and shapes of the components and the construction materials may be modified for particular circumstances or types of bags to be carried.

While various embodiments have been described above, it should be understood that they have been presented by way of example only, and not as limitations.

INDUSTRIAL APPLICABILITY

The collapsible golf bag cart 10 of the present invention is intended for use primarily by golfers who desire maximum convenience and safety while transporting a golf bag on a walking round. The cart 10 is lightweight and is can be folded into an extremely compact form to facilitate storage. It expands and folds with a minimum of effort. The expanded mode 14 is very stable for rolling and supporting the golf bag 12 during the round. The cart 10 also requires no straps or other fasteners to retain and support the golf bag, thus minimizing the amount of loose or dangling components and reducing effort.

For typical use, the golf bag cart 10 will begin in the compact mode 16, for storage. In this mode it has only the effective height of the rear wheels 76 and a lateral extent approximately equal to the width of the rear wheels 76 themselves plus the width of the pivot joint subassembly 26 so the cart easily fits into an automobile trunk or on a garage shelf. Even in collapsed mode 16, however, the wheels 24 are free to rotate and the cart 10 can be rolled to desired locations (providing that the friction brake 75 is not engaged).

When the golfer has moved the folded mode 16 cart to the desired location it is time to expand it to the mode where it is feasible to load a golf bag 12. To do this the golfer simply grasps the torso frame 32 (or the handle frame 136, as desired), disengages the pivot lock lever 128 and pulls upward from the base frame 30. This causes the RRG assembly 120 to rotate the central axle 64 which causes the rearward rotation and lateral expansion of the suspension system 62 of the rear wheels 76. As the rear wheels 76 will typically be on the ground this results in the fulcrum position of the pivot joint subassembly 26 to be lifted upward, resulting in the base struts 34 being angled upward and the torso strut 32 angling rearward of vertical to a lesser degree than if the base struts 34 remained horizontal to the ground. The shaping of the expanded cart also provides a gap such that the pockets of the golf bag 12 may comfortably fit between the bag and the pivot joint 26.

The front wheel subassembly 22 may be transitioned to the expanded mode either before or after the bag support subassembly 24. This expansion of the front wheel subassembly 22 is accomplished by manually releasing the yoke lock lever 60 and rotating the yoke 52 and front wheels 58 around the cross pin 36 to a position forward of and under the bag bottom cradle 40. The yoke lock lever 60 is then again engaged to lock the position.

Similarly, the handle subassembly 28 may be positioned time-independently of the bag support subassembly 24. The handle frame 136 is manually rotated about the handle pivot 46 to the desired position and secured at the optimal angle for the particular user. The angles of the handle grips 138 are also adjusted to the user's preference.

Once the cart 10 is in the expanded mode (FIGS. 1-3) the user will load the golf bag 12 such that the bag bottom is supported within the bag bottom cradle 40 and the collar or top of the bag is elastically captured in the resilient bag top cradle 48. The user then is positioned either directly behind the handle so as to be able to grasp either or both of the handle grips 136, or to one side in order to grasp only one of the handle grips 136. Thus the user can choose either to propel the cart 10 by pushing directly from behind or by guiding and pushing/pulling from a position walking beside the cart 10.

When the round is over, the golfer simply: removes the bag 12 from the cart 10; and reverses the above steps to return the cart 10 to the compact mode 16 and stores it again.

The extreme convenience, ease of operation, compactness of storage volume and light weight of the inventive cart 10 make it a joy to own and use and a desirable accessory for any golfer who wishes to walk the course without carrying the weight of the bag.

For the above, and other, reasons, it is expected that the collapsible golf bag cart 10 of the present invention will have widespread industrial applicability. Therefore, it is expected that the commercial utility of the present invention will be extensive and long lasting.

IN THE CLAIMS

While various embodiments have been described above, it should be understood that they have been presented by way of example only, and not limitation. Thus, the breadth and scope of a preferred embodiment should not be limited by any of the above described exemplary embodiments, but should be defined only in accordance with the following claims and their equivalents. 

What is claimed is:
 1. A collapsible golf bag cart, comprising: a pivot joint including a rotatable transverse central axle extending therethrough; a base frame supporting said pivot joint at its proximal end and having a front wheel structure pivotally attached to its distal end; a torso frame connected at its distal end to said pivot joint and pivotally connected to a handle at its distal end; and a pair of rear wheel suspensions pivotally connected to opposing ends of said transverse axle; wherein rotating said transverse central axle in one direction causes said rear wheel suspensions to expand outward and rearward with respect to said pivot into an expanded mode and rotating said central axle in the opposite direction causes said rear wheel suspensions to retract forward and inward with respect to said pivot joint into a compact mode.
 2. The golf bag cart of claim 1, wherein: said torso frame is operationally engaged with said transverse central axle through a rotational reversing gear system such that rotating said torso frame about said pivot joint causes said central axle to rotate in the opposite direction.
 3. The golf bag cart of claim 1, wherein: said rotatable transverse central axle includes a reciprocal rotational gear structure.
 4. The golf bag cart of claim 3, wherein: said reciprocal rotational gear structure includes a ring gear, a first reversing gear, a second reversing gear, and a central gear secured to said transverse axle.
 5. The golf bag cart of claim 5, and further including: a stop wedge portion of said central gear; an expansion limiter to limit rotation in one direction by abutting against said stop wedge; and a compact limiter to limit rotation in the opposite direction by abutting against said stop wedge.
 6. The golf bag cart of claim 1, and further including: a pivot lock lever mounted on said torso frame; and a rotationally stationary component secured to said base frame, said rotationally stationary component having an expansion stop and a compact stop for engaging said pivot lock lever at limits of rotation.
 7. The golf bag cart of claim 1, wherein: each said rear wheel suspension includes a leg strut pivotally attached near its proximal end to a strut bracket portion of a mounting plate secured on said transverse axle and attached to a rear wheel axle at its distal end, said leg strut including an extension portion opposite said pivot bracket from said rear axle; a first slide post extending through said mounting plate to engage said leg strut intermediate said strut bracket and said rear axle; a second slide post extending through said mounting plate to engage said extension portion of said leg strut; and a ramp structure, stationary with respect to said transverse axle, for engaging the opposite ends of said first slide post and said second slide post to force said leg strut to pivot outward at its distal when said transverse axle is rotated in one direction and to force said leg strut to pivot inward at its distal end when said transverse axle is rotated in the opposite direction.
 8. The golf bag cart of claim 7, wherein: each said rear wheel subsystem further includes a parallel link pivotally extending between said mounting plate and said rear wheel axle to form a parallelogram linkage with said leg strut.
 9. A collapsible golf bag cart system, comprising: a central pivot joint; a base frame connected to said central pivot joint; a torso frame rotationally connected to said central pivot joint; and a rear wheel subassembly rotationally connected to said central pivot joint; wherein each of said base frame, said torso frame and said rear wheel subassembly has an approximately equal longitudinal length.
 10. The collapsible golf bag cart system of claim 9, and further including a handle pivotally connected to said torso frame at a location displaced from said pivot joint.
 11. The collapsible golf bag cart system of claim 9, wherein said pivot joint includes a transverse central axle; and said torso frame is operationally engaged with said transverse central axle through a rotational reversing gear system such that rotating said torso frame about said pivot joint causes said central axle to rotate in the opposite direction.
 12. The collapsible golf bag cart system of claim 11, wherein said rear wheel subassembly rotates in conjunction with said transverse central axle.
 13. The collapsible golf bag cart system of claim 12, and further including a leg deployment ramp and pair of slide posts situated intermediate said central pivot joint on each side thereof; and wherein said rear wheel subassembly is caused to expand laterally when said transverse central axle is rotated in one direction and to retract laterally when said transverse central axle is rotated in the opposite direction.
 14. A handle assembly for a golf bag cart, comprising a handle frame; and a pair of grip handles mounted on associated grip pivots situated on opposite sides of said handle frame, wherein each said grip handle may be rotated on its associate grip pivot so as to extend in a range from downward, laterally outward, and upward from said handle frame.
 15. The handle assembly of claim 14, wherein each said grip handle engages a grip pivot on said handle frame.
 16. The handle assembly of claim 14, wherein said grip pivot has a range of motion extending from directly vertically downward, through straight outward to directly vertically outward and can be set in place in positions within said range.
 17. The handle assembly of claim 14, wherein said grip pivot is a ratchet structure. 